Catalyst systems

ABSTRACT

Catalyst systems suitable for tetramerizing ethylene to form 1-octene may include a catalyst including a reaction product of a chromium compound and a ligand having the structure according to Formula (II). In Formula (II), A and C may be independently chosen from phosphorus, arsenic, antimony, bismuth, and nitrogen; B may be a linking group between A and C; and R 1 , R 2 , R 3 , and R 4  may be independently chosen from a (C 1 -C 50 ) hydrocarbyl or a (C 1 -C 50 ) heterohydrocarbyl. The catalyst system may include a co-catalyst including a reaction product of an organoaluminum compound and an antifouling compound. The antifouling compound may include one or more quaternary salts; one or more organic acids, organic acid salts, esters, anhydrides, or combinations of these; one or more chlorinated hydrocarbons, chloro-aluminum alkyls, or combinations of these; one or more polyether alcohols; or one or more non-polymeric ethers.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ApplicationSer. No. 63/119,141 filed on Nov. 30, 2020 and entitled “CatalystSystems,” the entire contents of which are incorporated by reference inthe present disclosure. Additionally, this application claims thebenefit of and priority to U.S. Application Ser. No. 63/119,142 filed onNov. 30, 2020 and entitled “Catalyst Systems,” the entire contents ofwhich are incorporated by reference in the present disclosure.Additionally, this application claims the benefit of and priority toU.S. Application Ser. No. 63/119,206 filed on Nov. 30, 2020 and entitled“Catalyst Systems,” the entire contents of which are incorporated byreference in the present disclosure. Additionally, this applicationclaims the benefit of and priority to U.S. Application Ser. No.63/119,217 filed on Nov. 30, 2020 and entitled “Catalyst Systems,” theentire contents of which are incorporated by reference in the presentdisclosure. Additionally, this application claims the benefit of andpriority to U.S. Application Ser. No. 63/119,221 filed on Nov. 30, 2020and entitled “Catalyst Systems,” the entire contents of which areincorporated by reference in the present disclosure.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate chemicalprocessing and, more particularly, to catalyst systems utilized in suchchemical processing.

BACKGROUND

Linear alpha-olefins (“LAOs”) were historically produced from crackingof refinery products or products of non-selective oligomerization ofethylene as a broad olefin fraction. Demand for these compounds isrising in North America, Western Europe, and Asia. Currently, there areseveral industrial processes that produce LAOS. Notably, the ShellHigher Olefin Process (SHOP), which has been in operation since 1977,can be used to produce LAOS. The SHOP process employs a combination ofoligomerization and olefin metathesis chemistries to produce a varietyof LAOs using a Ni-based catalyst. INEOS, a global manufacturer ofpetrochemicals has also developed a proprietary process for synthesizinga wide range of LAOs with the flexibility to change distributions ofproducts to meet demand.

The demand for short chain alpha olefins, such as 1-octene and 1-hexene,has been rising as well. Specific chain length ranges of alpha-olefinsare crucial for specific applications. For example, short chain-lengths(e.g., 1-butene to 1-octene) are used to improve the rheological meltand solid resin properties of polyethylene. The main consumer of1-octene is the high-volume production of linear low-densitypolyethylene (LLDPE) and high-density polyethylene (HDPE), which expandseach year. Co-monomer alpha-olefin content is 1-2% for HDPE grades andreaches up to 30% for some LLDPE grades.

As such, 1-octene is a very important chemical feedstock that is inmarket demand. Aside from the processes discussed above, variouscatalysts have been developed for the tetramerization of ethylene toform 1-octene. However, these catalysts have deficiencies in severalrespects. As such, improved catalysts, which are suitable fortetramerization of ethylene to from 1-octene, are desired in theindustry.

SUMMARY

Fouling, as described herein, refers to the undesirable formation ofpolymers. Such polymers may form as side-products in the reaction ofethylene to form 1-octene when a catalyst system including chromium isused. However, as described herein, it has been discovered that theutilization of a co-catalyst that is a reaction product of anantifouling compound and an organoaluminum compound, may reduce fouling.As described herein, such antifouling compounds may include quaternarysalts, chlorinated hydrocarbons, and esters, and it is believed that theincorporation of such antifouling compounds into the catalyst system maybe responsible for reduced fouling. Moreover, in some embodiments, theutilization of the co-catalyst described herein may contribute tomaintaining the selectivity of 1-octene, or even enhancing theselectivity of 1-octene, as compared with similar catalyst systems thatdo not include the antifouling compound.

According to one or more embodiments, a catalyst system suitable fortetramerizing ethylene to form 1-octene may include a catalystcomprising a reaction product of a chromium compound and a ligand havingthe structure according to Formula (II).(R₁)(R₂)A-B-C(R₃)(R₄)   (II)

In Formula (II), A and C may be independently chosen from phosphorus,arsenic, antimony, bismuth, and nitrogen; B may be a linking groupbetween A and C; and R₁, R₂, R₃, and R₄ may be independently chosen froma (C₁-C₅₀) hydrocarbyl or a (C₁-C₅₀) heterohydrocarbyl. The catalystsystem may comprise a co-catalyst comprising a reaction product of anorganoaluminum compound and an antifouling compound. The antifoulingcompound may comprise one or more quaternary salts; one or more organicacids, organic acid salts, esters, anhydrides, or combinations of these;one or more chlorinated hydrocarbons, chloro-aluminum alkyls, orcombinations of these; one or more polyether alcohols; or one or morenon-polymeric ethers.

Additional features and advantages of the described embodiments will beset forth in the detailed description which follows, and in part will bereadily apparent to those skilled in the art from that description orrecognized by practicing the described embodiments, including thedetailed description which follows, as well as the claims.

DETAILED DESCRIPTION

Described herein are catalysts systems, which may be utilized to produce1-octene from ethylene by tetramerization. Also described herein aremethods for utilizing such catalyst systems. The presently describedcatalyst systems may include a catalyst and a co-catalyst, as aredescribed in detail herein. In one or more embodiments described herein,the catalyst may comprise chromium and, in some embodiments, may be thereaction product of a chromium compound and a ligand. The co-catalystmay be the reaction product of at least an antifouling compound and anorganoaluminum compound.

In one or more embodiments, the catalyst systems described herein may beused to selectively oligomerize ethylene to produce 1-octene, whilereducing undesirable polymerization, sometimes referred to in thisdisclosure as “fouling.” For example, reactor fouling may occur at leastpartially due to the formation of solid polyethylene-based residues,which may reduce fluid flow and/or fully block or at least partiallyblock fluids in a reactor system from flowing at a desired rate. Withoutbeing bound by any particular theory, it is believed that theincorporation of the antifouling compound into the catalyst systemreduces fouling.

It should be understood that the catalyst systems presently describedmay not completely eliminate fouling during a reaction. However, in oneor more embodiments, these catalyst systems reduce fouling as comparedwith catalyst systems which do not include the antifouling compound asdescribed in the present disclosure. Also, it should be understood that,while the catalyst systems of the present disclosure may be useful inethylene oligomerization reactions, such as ethylene dimerization toform 1-butene, they may also be useful for the catalysis of otherchemical reactions, and the catalyst systems described in thisdisclosure should not be considered limited in their use to thetetramerization of ethylene to form 1-octene. It should further beunderstood that the antifouling agents described in this disclosure maybe incorporated with other catalyst systems which contain, for example,non-chromium based catalysts.

As used in this disclosure, a “catalyst” refers to any substance thatincreases the rate of a specific chemical reaction. Catalysts describedin this disclosure may be utilized to promote various reactions, suchas, but not limited to, tetramerization of ethylene to form 1-octene.Catalysts are generally not consumed in a reaction, but as would beunderstood in the art, may have reduced catalytic activity over time andneed to be replaced and/or regenerated.

As used in this disclosure, a “co-catalyst” generally refers to anysubstance or chemical agent that brings about catalyst in conjunctionwith one or more catalysts. In some embodiments, a catalyst may haveindependent catalytic functionality, while in other embodiments, thecatalyst may only have substantial catalytic functionality when pairedwith a co-catalyst. It should be understood that the catalyst andco-catalyst may be, in some embodiments, bonded or formed in a complex,but in other embodiments are not bonded or present in a complex. Someco-catalysts may be said to “activate” a catalyst, which may increasecatalytic functionality.

Additionally, as used in this disclosure, a “catalyst system” refers toany catalytically functional collection of chemical species. In someembodiments, a catalyst system may include a catalyst and a co-catalyst.In additional embodiments, a catalyst system may include additionalcomponents, such as, for example, additional co-catalysts ornon-catalytic additives which may serve other purposes.

As described herein, a “reaction product” refers to a chemical speciesformed from the reaction of any two or more reactant species. A reactionproduct may result in a covalent or ionic bond, coordination, or otherinteraction between reactant species. In some embodiments, two or morereaction products may result from the reaction of the reactant species,and all of these possible produced chemical species are included in thereactant product as described herein.

When used to describe certain carbon atom-containing chemical groups, aparenthetical expression having the form “(C_(x)-C_(y))” means that theunsubstituted form of the chemical group has from x carbon atoms to ycarbon atoms, inclusive of x and y. For example, a (C₁-C₅₀) alkyl groupis an alkyl group having from 1 to 50 carbon atoms in its unsubstitutedform. In some embodiments and general structures, certain chemicalgroups may be substituted by one or more substituents. A substitutedchemical group defined using the “(C_(x)-C_(y))” parenthetical maycontain more than y carbon atoms depending on the identity of anysubstituents. For example, a “(C₁-C₅₀) alkyl substituted with exactlyone phenyl (—C₆H₅)” may contain from 7 to 56 carbon atoms. Thus, ingeneral when a chemical group defined using the “(C_(x)-C_(y))”parenthetical is substituted by one or more carbon atom-containingsubstituents, the minimum and maximum total number of carbon atoms ofthe chemical group is determined by adding to both x and y the combinedsum of the number of carbon atoms from all of the carbon atom-containingsubstituents.

The term “substitution” means that at least one hydrogen atom (—H)bonded to a carbon atom or heteroatom of a corresponding unsubstitutedcompound or functional group is replaced by a substituent. Substituentsmay be any suitable functional group or radical that could replace ahydrogen atom bonded to a carbon atom or heteroatom of a correspondingunsubstituted compound. For example, substituents may include, but arenot limited to, hydrocarbyls, cyclohydrocarbyls, aryls, halogens, andamines.

The term “—H” means a hydrogen or hydrogen radical that is covalentlybonded to another atom. “Hydrogen” and “—H” are interchangeable, andunless clearly specified have identical meanings.

The term “hydrocarbyl” means a monovalent radical resulting from removalof any hydrogen atom from a hydrocarbon, including aromatichydrocarbons, non-aromatic hydrocarbons, cyclic or acyclic hydrocarbons,saturated or unsaturated hydrocarbons, straight chain or branched chainhydrocarbons, and substituted or unsubstituted hydrocarbons.

The term “heterohydrocarbyl” refers to a hydrocarbyl, from which atleast one carbon atom has been replaced with a heteroatom. Examples ofheteroatoms include, without limitation, oxygen, nitrogen, sulfur, andphosphorus.

The term “cyclohydrocarbyl” means an aromatic or non-aromatic, cyclichydrocarbyl having at least three carbon atoms, including monocyclic andpolycyclic hydrocarbyls, fused and non-fused polycyclic hydrocarbyls,and bicyclic hydrocarbyls, non-aromatic saturated or unsaturated cyclichydrocarbyls, and substituted or unsubstituted hydrocarbyls.

The term “aryl” means an aromatic hydrocarbon radical, in which thecarbon atoms of the aromatic system may be substituted or unsubstituted.Aryls include monocyclic, bicyclic and tricyclic aromatic hydrocarbonradicals. A monocyclic aromatic hydrocarbon radical includes onearomatic ring; a bicyclic aromatic hydrocarbon radical has two rings;and a tricyclic aromatic hydrocarbon radical has three rings. When thebicyclic or tricyclic aromatic hydrocarbon radical is present, at leastone of the rings of the radical is aromatic. The other ring or rings ofthe aromatic radical may be independently fused or non-fused andaromatic or non-aromatic. Non-limiting examples of aryls include phenyl;fluorenyl; tetrahydrofluorenyl; indacenyl; hexahydroindacenyl; indenyl;dihydroindenyl; naphthyl; tetrahydronaphthyl; and phenanthrenyl.

The term “alkyl” means a saturated hydrocarbon radical that may belinear or branched. Accordingly, the term “(C₁-C₂₀) alkyl” means asaturated linear or branched hydrocarbon radical of from 1 to 20 carbonatoms that is unsubstituted or substituted. Examples of unsubstituted(C₁-C₂₀) alkyl include methyl; ethyl; 1-propyl; 2-propyl; 1-butyl;2-butyl; 2-methylpropyl; 1,1-dimethylethyl; 1-pentyl; 1-hexyl; 1-heptyl;1-nonyl; and 1-decyl. Examples of substituted (C₁-C₂₀) alkyl includetrifluoromethyl and trifluoroethyl.

The term “saturated” means lacking carbon-carbon double bonds,carbon-carbon triple bonds, and (in heteroatom-containing groups)carbon-nitrogen, carbon-phosphorous, and carbon-silicon double bonds.Where a saturated chemical group is substituted by one or moresubstituents, one or more double and/or triple bonds optionally may bepresent in substituents. The term “unsaturated” means containing one ormore carbon-carbon double bonds or carbon-carbon triple bonds, or (inheteroatom-containing groups) one or more carbon-nitrogen double bonds,carbon-phosphorous double bonds, or carbon-silicon double bonds, notincluding double bonds that may be present in substituents, if any, orin aromatic rings or heteroaromatic rings, if any.

In one or more embodiments, the catalyst comprises chromium. It shouldbe understood that, as contemplated herein, the catalyst may be anychemical compound that includes chromium that is catalyticallyfunctional for, without limitation, promoting the selectivetetramorization of ethylene to from 1-octene.

In one or more embodiments, the catalyst includes a reaction product ofa chromium compound and a ligand. It should be understood that thechromium complexes described herein, which may coordinate with ligands,are not necessarily limited in structure, but includes chromium. In oneor more embodiments, the chromium compound includes an organic chromiumsalt, an inorganic chromium salt, a chromium complex, or combinations ofthese. In some embodiments, the chromium compound includes chromiumtrichloride tris-tetrahydrofuran complex, (benzene)tricarbonyl chromium,chromium (III) octanoate, chromium (III) acetylacetonoate, chromiumhexacarbonyl, chromium (III) 2-ethylhexanoate, or combinations of these.

It should be understood that the ligands described herein, which maycoordinate with chromium of the chromium complex are not necessarilylimited in structure. However, in some embodiments, the ligand may havea structure according to formula (I):(R)_(n)A-B-C(R)_(m)   (I)

In formula (I), A and C are independently chosen from phosphorus (P),arsenic (As), antimony (Sb), oxygen (O), bismuth (Bi), sulfur (S),selenium (Se), or nitrogen (N); B is a linking group between A and C;each R is independently chosen from any (C₁-C₅₀) homo-hydrocarbyl or(C₁-C₅₀) hetero-hydrocarbyl group, where at least one R group may besubstituted with a polar substituent; and n and m are determined by therespective valence and oxidation state of A and C. In some embodiments,A and C of the ligand of formula (I) may function as electron donors forcoordination with the chromium compound. As described herein, an“electron donor” refers to any chemical substituent that donateselectron used in chemical (including dative covalent) bond formation.

In one or more embodiments, the ligand may have a structure according toformula (II):(R₁)(R₂)A-B-C(R₃)(R₄)   (II)

In formula (II), A and C are independently chosen from phosphorus (P),arsenic (As), antimony (Sb), bismuth (Bi), or nitrogen (N); B is alinking group between A and C; R₁, R₂, R₃, and R₄ are independentlychosen from any (C₁-C₅₀) hydrocarbyl. In one or more embodiments, atleast one of R₁, R₂, R₃, and R₄ may be substituted with a polarsubstituent. In one or more embodiments, the (C₁-C₅₀) hydrocarbyl groupmay be a (C₁-C₅₀) homo-hydrocarbyl or (C₁-C₅₀) hetero-hydrocarbyl group.As described herein, a “polar substituent” refers to any chemicalsubstituent with a permanent electric dipole moment, as defined by theIUPAC. Example polar substituents include methoxy, ethoxy, isopropoxy,(C₃-C₂₀)alkoxy, phenoxy, pentafluorophenoxy, trimethylsiloxy,dimethylamino, methylsulfanyl, tosyl, methoxymethy, methylthiomethyl,1,3-oxazolyl, methomethoxy, hydroxyl, amino, phosphino, arsino, stibino,sulphate, and nitro.

In some embodiments, up to four of R₁, R₂, R₃, and R₄ may havesubstituents on the atom adjacent to the atom bound to A or C. In someembodiments, each of R₁, R₂, R₃, and R₄ may be aromatic, includingheteroaromatic, and are substituted by any substituent on an atomadjacent to the atom bound to A or C. In some embodiments, not more thantwo of R₁, R₂, R₃, and R₄, if they are aromatic, may have substituentson the atom adjacent to the atom bound to A or C. In some embodiments,any polar substituents on R₁, R₂, R₃, and R₄, if they are aromatic, arenot on the atom adjacent to the atom bound to A or C. For example, atleast one of R₁, R₂, R₃, and R₄, if aromatic, may be substituted with apolar substituent on the 2^(nd) or further atom from the atom bound to Aor C. In some embodiments, any polar substituent on one or more of R₁,R₂, R₃, and R₄ may be electron donating. In some embodiments, any of thegroups R₁, R₂, R₃, and R₄ may independently be linked to one or more ofeach other or to the linking group B to form a cyclic structure togetherwith A and C, A and B or B and C. In some embodiments, R₁, R₂, R₃, andR₄ may be independently chosen from a benzyl, phenyl, tolyl, xylyl,mesityl, biphenyl, naphthyl, anthracenyl, methoxy, ethoxy, phenoxy,tolyloxy, dimethylamino, diethylamino, methylethylamino, thiophenyl,pyridyl, thioethyl, thiophenoxy, trimethylsilyl, dimethylhydrazyl,methyl, ethyl, ethenyl, propyl, butyl, propenyl, propynyl, cyclopentyl,cyclohexyl, ferrocenyl, or tetrahydrofuranyl group.

In some embodiments, A and/or C may be independently oxidized by S, Se,N or O, where the valence of A and/or C allows for such oxidation. Forexample, A and C may be independently phosphorus or phosphorus oxidizedby S or Se or N or O.

In some embodiments, B may be an organic linking group comprising a(C₁-C₅₀) hydrocarbyl, a (C₁-C₅₀) substituted hydrocarbyl, a (C₁-C₅₀)heterohydrocarbyl, and a (C₁-C₅₀) substituted heterohydrocarbyl; aninorganic linking group comprising single atom links; ionic links; and agroup comprising methylene, dimethylmethylene, 1,2-ethane,1,2-phenylene, 1,2-propane, 1,2-catechol, 1,2-dimethylhydrazine,—B(R₅)—, —Si(R₅)₂—, —P(R₅)— and —N(R₅)—, where R₅ is hydrogen, a(C₁-C₅₀) hydrocarbyl or a (C₁-C₅₀) substituted hydrocarbyl, a (C₁-C₅₀)substituted heteroatom or a halogen. For example, B may be —N(R₅)—,where R₅ is a (C₁-C₅₀) hydrocarbyl or a (C₁-C₅₀) substituted hydrocarbylgroup. R₅ may be hydrogen or may be selected from the groups consistingof alkyl, substituted alkyl, aryl, substituted aryl, aryloxy,substituted aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy,alkoxy, aminocarbonyl, carbonylamino, dialkylamino, silyl groups orderivatives thereof, and aryl substituted with any of thesesubstituents. For example, R₅ may be an isopropyl, a 1-cyclohexylethyl,a 2-methylcyclohexyl, or a 2-octyl group. In some embodiments, B may bea single atom spacer. As described herein, a “single atom linkingspacer” refers to a substituted or non-substituted atom that is bounddirectly to A and C. In one or more embodiments, B is not bound to asecond ligand, such as a second PNP ligand.

Without intending to be bound by theory, the electronic properties ofthe ligand, whether moieties of the ligand are electron donors orelectron withdrawers affect the binding strength of ethylene to thecatalytic metal center. Additionally, the bulkiness of the ligand mayintroduce steric hindrances which also may affect the binding strengthof ethylene to the metal center. Accordingly, the ligand may affect thereactivity and selectivity of the catalyst toward the formation of1-octene.

The chromium compound and the ligand may be produced using proceduresand methods known in the art. For example, procedures and methods forproducing the chromium compound and the ligand are described in U.S.Pat. No. 7,297,832, which is incorporated by reference in its entirety.

As described herein, the catalyst system also includes a co-catalyst. Inthe embodiments described herein, the co-catalyst may be the reactionproduct of an organoaluminum compound and the antifouling compound. Itshould be understood that the organoaluminum compound may comprisemultiple chemical species, or a single chemical species. For example, inone or more embodiments, the co-catalyst may comprise a reaction productof the antifouling compound and methylaluminoxane. In one or moreembodiments, the co-catalyst may comprises a reaction product of theantifouling compound, methylaluminoxane, and an alkyl aluminum compound.Likewise, the antifouling compound may comprise multiple chemicalspecies, or a single chemical species.

In one or more embodiments, the co-catalyst may be formed from anorganoaluminum compound. As described herein, an “organoaluminumcompound” refers to any chemical compound that includes at least onealuminum atom and any organic moiety. It should be appreciated that theorganoaluminum compound may include several chemical species, or may bea single chemical species.

In some embodiments, the organoaluminum complex may be an alkyl aluminumcompound. The aluminum alkyl compounds described herein may have ageneralized structure shown in formula (III):

where R₆, R₇ and R₈ may each be a hydrogen atom or a (C₁-C₂₀)hydrocarbyl group an oxygen-containing moiety, or a halide. Inembodiments, the (C₁-C₂₀) hydrocarbyl group may be a substituted orunsubstituted (C₁-C₂₀) linear or branched hydrocarbyl group. In one ormore embodiments, R₃, R₄, and R₅ may each be a hydrogen or a linear orbranched (C₁-C₂₀) alkyl group. In additional embodiments, the alkylaluminum compound may be an aluminoxane structure (i.e., a partialhydrolysate of trialkylaluminum compounds). For example, and not by wayof limitation, suitable aluminum alkyl compounds may includetrimethylaluminium, triethylaluminum, tripropylaluminum,tri-iso-butylaluminum, diisobutyialuminium hydride, trihexylaluminum,tri-n-octylaluminium, methylaluminium dichloride, ethylaluminiumdichloride, dimethylaluminium chloride, diethylaluminium chloride,aluminium isopropoxide, ethylaluminiumsesquichloride,methylaluminiumsesquichloride, methylaluminoxane (MAO), ethylaluminoxane(EAO), and modified alkylaluminoxanes, such as modifiedmethylaluminoxane (MMAO). As described herein, a “modifiedalkylaluminoxane” refers to a alkylaluminoxane that includes one or moremodifier groups, such as isobuytyl or n-octyl groups in addition to thealkyl groups. In one or more embodiments, the organoaluminum compound ofthe catalyst system may comprise, consist essentially of, or consist ofany of these compounds.

Without intending to be bound by theory, the alky aluminum compound maybe operable to remove impurities, or poisons that may have a negativeeffect on the catalyst. Additionally, the alkyl aluminum compound may beoperable to alkylate the chromium complex. Furthermore, the alkylaluminum compound may be operable to activate the chromium complex toallow the coordination of the ethylene with the catalyst.

In one or more embodiments, the co-catalyst may be formed from anantifouling compound. As described herein, an “antifouling compound”refers to any chemical compound that decreases fouling by polymerproduction. It should be appreciated that the antifouling compound mayinclude several chemical species, or may be a single chemical species.

In some embodiments, the antifouling compound may be a quaternary salt.As described herein, a “quaternary salt” refers to any salt including aquaternary compound. As described herein, a “quaternary compound” refersto any cation that includes a central positively charged atom with foursubstituents. The quaternary salts described herein may have ageneralized structure shown in formula (IV):

In formula (IV), X is a nonmetal element from Group 15 or Group 16 ofthe International Union of Pure and Applied Chemistry periodic table ofthe elements (IUPAC periodic table); Y is an anion; and R₉, R₁₀, R₁₁,and R₁₂ are independently chosen from hydrogen or a (C₁-050) hydrocarbylgroup. In one or more embodiments, the (C₁-C₅₀) hydrocarbyl group may bea substituted or unsubstituted (C₁-C₅₀) linear or branched hydrocarbylgroup. In one or more embodiments, R₉, R₁₀, R₁₁, and R₁₂ are eachindependently chose from a hydrogen, an alkyl group, or an aryl group.In some embodiments, X is nitrogen (N), phosphorus (P), arsenic (As), orsulfur (S). In embodiments where X is nitrogen, the quaternary salt maybe an ammonium salt. In embodiments where X is phosphorus, thequaternary salt may be a phosphonium salt. In embodiments, where X issulfur, the quaternary salt may be a sulfonium salt. In someembodiments, Y is a halogen, a carbonate, a nitrate, a sulfate, aphosphate, or a sulphonate. For example, the quaternary salt of formula(IV) may include nitrogen as X and bromine as Y (i.e., the quaternarysalt of formula (IV) may a quaternary ammonium salt).

Without being bound by any particular theory, it is believed that thereaction between the organoaluminum compound and the antifoulingcompound may produce various chemical compounds. That is, theco-catalyst may include one or more chemical compounds, each of whichare reaction products of the organoaluminum compound and the antifoulingcompound. In embodiments wherein the organoaluminum compound is thealuminum alkyl compound of formula (VI) and the antifouling compound isthe quaternary salt of formula (VII), the reaction product of theorganoaluminum compound and the antifouling compound may be a quaternarysalt including a quaternary compound as the cation and an aluminumcompound as the anion. An example reaction of the aluminum alkylcompound of formula (III) and a quaternary salt of formula (IV) is shownin reaction scheme (I):

In some embodiments, the antifouling compound may be an organic acid, aderivative of an organic acid, or combinations of these. As describedherein, a “derivative of an organic acid” refers to any chemicalcompound derived from the organic acid. For example, derivatives of anorganic acid may be a salt of the organic acid, an ester derived fromthe organic acid, an anhydride derived from the organic acid, orcombinations of these. The organic acids described herein may have ageneralized structure shown in formula (V):

The organic acid salts described herein may have a generalized structureshown in formula (VI):

The esters described herein may have a generalized structure shown informula (VII):

The anhydrides described herein may have a generalized structure shownin formula (VIII):

In formulas (V)-(VIII), R₁₃ and R₁₄ are independently chosen from anunsubstituted hydrocarbyl group or a substituted hydrocarbyl group; andM is an element from Group 1 or Group 2 of the International Union ofPure and Applied Chemistry periodic table of the elements (IUPACperiodic table).

Without being bound by any particular theory, it is believed that thereaction between the organoaluminum compound and the antifoulingcompound may produce various chemical compounds. An example reaction ofthe aluminum alkyl compound of formula (III) and the ester of formula(VII) is shown in reaction scheme (II):

In some embodiments, the antifouling compound may be a chlorinatedhydrocarbon, a chloro-aluminum alkyl, or combinations of these. Asdescribed herein, a “chlorinated hydrocarbon” refers to any organicchemical compound that includes at least one covalently bonded atom ofchlorine that has an effect on the chemical behavior on the organicchemical compound. For example, a chlorinated hydrocarbon may be achloroalkane (i.e., an alkane with one or more hydrogens substituted bychlorine). The chloro-aluminum alkyls described herein may have ageneralized structure shown in formula (IX):

In formula (IX), R₁₅ and R₁₆ are independently chosen from anunsubstituted hydrocarbyl group or a substituted hydrocarbyl group. Insome embodiments, the antifouling compound is hexachloroethane (C₂Cl₆).

Without being bound by any particular theory, it is believed that thereaction between the organoaluminum compound and the antifoulingcompound may produce various chemical compounds. An example reaction ofthe aluminum alkyl compound of formula (III) and the chloro-aluminumalkyl of formula (IX) is shown in reaction scheme (III):

Without intending to be bound by theory, it is believed that thechloride of the chlorinated hydrocarbon may coordinate with a vacantcoordination site on the metal center such that the formation of1-octene may be favored and the formation of polymeric by-products maybe disfavored.

In one or more embodiments, the antifouling compound may be a polyetheralcohol. In some embodiments, the polyether alcohol may include monomerunits comprising one or more carbon chains separating ether moieties.For example, the polyether alcohols described herein may have ageneralized structure shown in formula (X):

In formula (X), R₁₇ is chosen from an unsubstituted hydrocarbyl group ora substituted hydrocarbyl group; m is an integer of from 1 to 100; and nis an integer from 1 to 20. In some embodiments, R₁₇ nay be anunsubstituted hydrocarbyl group that includes at least 1 carbon atom, atleast 2 carbon atoms, at least 3 carbon atoms, at least 4 carbon atoms,at least 5 carbon atoms, at least 6 carbon atoms, at least 7 carbonatoms, at least 8 carbon atoms, at least 8 carbon atoms, at least 9carbon atoms, at least 10 carbon atoms, at least 11 carbon atoms, or atleast 12 carbon atoms. In some embodiments, m is an integer of from 1 to75, from 1 to 50, from 1 to 25, from 25 to 100, from 25 to 75, from 25to 50, from 50 to 100, from 50 to 75, or from 75 to 100. In someembodiments, n is an integer of from 1 to 15, from 1 to 10, from 1 to 5,from 5 to 20, from 5 to 15, from 5 to 10, from 10 to 20, from 10 to 15,or from 15 to 20.

Without being bound by any particular theory, it is believed that thereaction between the organoaluminum compound and the antifoulingcompound may produce various chemical compounds. An example reaction ofthe aluminum alkyl compound of formula (III) and the polyether alcoholof formula (X) is shown in reaction scheme (IV):

In some embodiments, the antifouling compound may include one or morenon-polymeric ethers. The non-polymeric ethers may include cyclicnon-polymeric ethers such as, but not limited to, tetrahydrofuran (TIP),a dioxane, a tetrahydropyran (THP), or combinations of these. Asdescribed herein, a “non-polymeric” ethers refers to any chemicalcompound that includes one or more ethers but do not include long etherpolymer chains. Generally, such non-polymeric ethers comprise one or twoether moieties, and comprise less than 10 ether moieties.

Without intending to be bound by theory, the reaction products of theorganoaluminum compound and the antifouling compound may function as asurfactant and affect the ion-pair of the metal activation center of thecatalyst. This may affect the coordination of ethylene with the metalactivation center and the degree of chain-transfer predominant withrespect to chain propagation. By controlling the chain propagation, thereaction products of the organoaluminum compound and the antifoulingcompound may increase the product selectivity of 1-octene and reduce theproduction of large polymers, resulting in reduced fouling. Furthermore,it is contemplated that in one or more embodiments the reactions betweenthe quaternary salt and the organoaluminum compound are relatively fastand that there are little to no free quaternary salts remaining in thecatalytic system once the quaternary salt and organoaluminum compoundreact.

It should be understood that the co-catalysts contemplated herein mayinclude a number of different chemical species. However, as described inembodiments herein, these co-catalyst species share certain structuresand can be commonly classified by moiety or structure.

In one or more embodiments described herein, the antifouling compoundand organoaluminum complex may have a molar ratio of from 0.001 to 1,such as from 0.01 to 0.1. For example, according to embodiments, themolar ratio of antifouling compound to organoaluminum complex may befrom 0.001 to 0.01, from 0.01 to 0.02, from 0.02 to 0.03, from 0.03 to0.04, from 0.04 to 0.05, from 0.05 to 0.06, from 0.06 to 0.07, from 0.07to 0.08, from 0.08 to 0.09, from 0.09 to 0.1, from 0.1, to 0.2, from 0.2to 0.3, from 0.3 to 0.4, from 0.4 to 0.5, from 0.5 to 0.6, from 0.6 to0.7, from 0.7 to 0.8, from 0.8 to 0.9, from 0.9 to 1, or any combinationof these ranges, such as any subgroup encompassed by any combination ofthese ranges.

According to one or more embodiments, the catalyst system may furthercomprise additional co-catalysts and/or additives. It should beunderstood that these additional co-catalysts and/or additives areoptional and are not included in all embodiments described herein.Examples of additional co-catalysts and/or additives include, withoutlimitation, any of the organoaluminium compounds described herein whichform the co-catalyst (e.g. diisobutylaluminium hydride or and TEAL)could also be added to the catalyst system. Such additional co-catalystsmay be present if an excess amount of organoaluminum compound is addedto form the co-catalyst, such that all antifouling complex is reacted byexcess organoaluminum compound remains in the solution.

In one or more embodiments, ethylene may be contacted with the catalystsystem described herein to from a product comprising 1-octene.Contacting may generally include any mixing, combining, etc. of thereactant ethylene with the catalyst system. In one or more embodiments,the catalyst and co-catalyst may be separately prepared, and thencombined, prior to contacting of the catalyst system with ethylene. Inone or more embodiments, the ethylene may be contacted with the catalystsystem in the presence of hydrogen.

The reaction may be performed as a batch reaction or as a continuousprocess reaction, such as a continuous stir tank reactor process.According to further embodiments, the pressure of the reactor may befrom 5 bar to 120 bar (such as from 20 bar to 60 bar), and the reactortemperature may be from 25 ° C. to 180 ° C. (such as from 30 ° C. to 120° C.). However, process conditions outside of these ranges arecontemplated, especially in view of the specific design of the reactorsystem and concentrations of the reactants and catalysts.

It should be understood that, in one or more embodiments, similar oridentical catalyst systems which do not include the antifouling compoundmay exhibit increased fouling. In one or more embodiments, theintroduction of the antifouling agent into a catalyst system maysuppress polymer formation while not greatly reducing catalytic activityof 1-octene formation. In one embodiment, polymer formation (fouling)may be reduced by at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%,90%, or even 95% by the inclusion of an antifouling compound. In oneembodiment, 1-octene production may be increased, stay the same, or maydecrease by less than or equal to 50%, 40%, 30%, 20%, 10% or even 5% bythe inclusion of an antifouling compound. In some embodiments,antifouling, compounds may both reduce the polymer formation (such as byat least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or even 95%)and increase, not effect, or decrease 1-octene production rate by lessthan or equal to 50%, 40%, 30%, 20%, 10% or even 5%. Reduction inpolymer formation rates and catalytic activity on a percentage basis arebased on catalyst systems which are formed from the antifoulingcompounds described herein as compared with catalyst systems which arevoid of an antifouling compound.

EXAMPLES

The various aspects of the present disclosure will be further clarifiedby the following examples. The examples are illustrative in nature andshould not be understood to limit the subject matter of the presentdisclosure.

Catalyst Production Method

In the following examples, the catalyst was produced by dissolving 0.86milligrams (mg) of Cr(acac)₃ and 1.07 mg ofN,N-bis(diphenylphosphino)isopropylamine (Chemical Abstracts Service(CAS) No. 60981-68-2) in 100 milliliters (ml) of anhydrousmethylcyclohexane (MCH) in an inert and moisture-free environment, andmixing for 30 minutes to produce a catalyst solution.

Co-Catalyst Production Method

In the following examples, the co-catalyst was produced by mixing 480 mgof MMAO-3A (CAS No. 146905-79-5) in heptane (7 wt. % aluminum) and anantifouling compound (AFC) such that the molar ratio of the AFC toaluminum (AFC:Al) was from 0.001 to 1 or from 0.01 to 0.1.

Ethylene Tetramerization Procedure

In the following examples, an ethylene tetramerization process (alsoreferred to as a run) was conducted using the same general procedure.Each run was conducted in a 250 milliliter (ml) autoclave reactor unit.Before each run, the autoclave reactor unit was vacuum purged withultrapure nitrogen to remove oxygen and moisture, which may bedetrimental to the ethylene tetramerization reaction, and then filledwith a desired amount of anhydrous MCH as a solvent. Once the autoclavereactor unit was prepared, the catalyst solution and co-catalyst, asdescribed previously, were separately into the autoclave reactor unitsuch that the molar ratio of the co-catalyst to the catalyst(Co-Cat:Cat) was approximately 0.1. Subsequently, approximately 3 bar ofultrapure molecular hydrogen was charged to the autoclave reactor unit,which was then heated to a temperature of 45° C. In order to initiatethe run, 45 bar of ethylene was charged to the autoclave rector unit.Once a desired run time of 60 min. was reached, the run was terminatedby injecting 2.0 ml of methanol into the autoclave reactor unit, whichwas then depressurized. Any solid polymer produced was collected fromthe autoclave reactor unit, filtered, dried overnight in an oven at 110°C., and weighed.

Example 1

In Example 1, an ethylene tetramerization process, as describedpreviously, was conducted using an AFC having a structure according toformula (XI):

The results of Example 1 are reported in Table 1.

Example 2

In Example 2, an ethylene tetramerization process, as describedpreviously, was conducted using an AFC having a structure according toformula (XII):

The results of Example 2 are reported in Table 1.

Example 3

In Example 3, an ethylene tetramerization process, as describedpreviously, was conducted using an AFC having a structure according toformula (XIII):

The results of Example 3 are reported in Table 1.

Comparative Example 4

In Comparative Example 4, an ethylene tetramerization process, asdescribed previously, was conducted in a manner similar to Examples 1-3,but no AFC was used (i.e., the solution of MMAO-3A in heptane wasinjected alone). The results of Comparative Example 4 are reported inTable 1.

TABLE 1 Molar Ratio Activity (mol 1- 1- Cr(acac)₃ PNP Al (Co-1-octene/mol Hexene Octene Polymer Example (mmol) (mmol) (mmol) Cat:Cat)catalyst/hour) (mol. %) (mol. %) (wt. %) Example 1 0.0025 0.0025 1.250.1 124,630 9.52 74.09 5.73 Example 2 0.0025 0.0025 1.25 0.1 113,1809.88 74.65 6.14 Example 3 0.0025 0.0025 1.25 0.1 100,292 9.23 74.47 5.71Comparative 0.0025 0.0025 1.25 — 102,580 10.21 74.82 8.42 Example 4Reaction Conditions-Temperature: 45° C.; C₂H₄ Pressure: 45 bar; H₂Pressure: 3 bar; Run Time: 60 min

As shown in Table 1, the catalyst systems of Examples 1-3 each resultedin lower production of polymer than the catalyst system of ComparativeExample 4. Accordingly, the catalyst systems of Examples 1-3 provide abenefit over the catalyst system of Comparative Example 4 by providing arelatively low polymer selectivity. Furthermore, the catalyst systems ofExamples 1-3 generally provided comparable activity and selectivity for1-octene to the catalyst system of Comparative Example 4, evensurpassing the activity for 1-octene of the catalyst system ofComparative Example 4 in some cases.

In a first aspect of the present disclosure, a catalyst system suitablefor tetramerizing ethylene to form 1-octene may include a catalystcomprising a reaction product of a chromium compound and a ligand havingthe structure according to Formula (II). In Formula (II), A and C may beindependently chosen from phosphorus, arsenic, antimony, bismuth, andnitrogen; B may be a linking group between A and C; and R₁, R₂, R₃, andR₄ may be independently chosen from a (C₁-C₅₀) hydrocarbyl or a (C₁-C₅₀)heterohydrocarbyl. The catalyst system may comprise a co-catalystcomprising a reaction product of an organoaluminum compound and anantifouling compound. The antifouling compound may comprise one or morequaternary salts; one or more organic acids, organic acid salts, esters,anhydrides, or combinations of these; one or more chlorinatedhydrocarbons, chloro-aluminum alkyls, or combinations of these; one ormore polyether alcohols; or one or more non-polymeric ethers.

A second aspect of the present disclosure may include the first aspect,where the antifouling compound comprises one or more quaternary salts.

A third aspect of the present disclosure may include either the first orsecond aspect, where the antifouling compound comprises one or moreorganic acids.

A fourth aspect of the present disclosure may include any of the firstthrough third aspects, where the antifouling compound comprises one ormore organic acid salts.

A fifth aspect of the present disclosure may include any of the firstthrough fourth aspects, where the antifouling compound comprises one ormore esters.

A sixth aspect of the present disclosure may include any of the firstthrough fifth aspects, where the antifouling compound comprises one ormore anhydrides.

A seventh aspect of the present disclosure may include any of the firstthrough sixth aspects, where the antifouling compound comprises one ormore chlorinated hydrocarbons.

An eighth aspect of the present disclosure may include any of the firstthrough seventh aspects, where the antifouling compound comprises one ormore chloro-aluminum alkyls.

A ninth aspect of the present disclosure may include any of the firstthrough eighth aspects, where the antifouling compound comprises one ormore polyether alcohols.

A tenth aspect of the present disclosure may include any of the firstthrough ninth aspects, where the antifouling compound comprises one ormore non-polymeric ethers.

An eleventh aspect of the present disclosure may include any of thefirst through tenth aspects, where the chromium compound comprises oneor more of an organic chromium salt, an inorganic chromium salt, and achromium complex.

A twelfth aspect of the present disclosure may include any of the firstthrough eleventh aspects, where the chromium compound comprises one ormore of chromium trichloride tris-tetrahydrofuran complex,(benzene)tricarbonyl chromium, chromium (III) octanoate, chromium (III)acetylacetonoate, chromium hexacarbonyl, and chromium (III)2-ethylhexanoate.

A thirteenth aspect of the present disclosure may include any of thefirst through twelfth aspects, where the organoaluminum compound has thestructure according to formula (III) in which R₆, R₇, and R₈ are eachselected from a hydrogen atom and a (C₁-C₂₀) hydrocarbyl group.

A fourteenth aspect of the present disclosure may include any of thefirst through thirteenth aspects, where the organoaluminum compoundcomprises one or more of trimethylaluminium, triethylaluminum,tripropylaluminum, tri-iso-butylaluminum, diisobutylaluminium hydride,trihexylaluminum, tri-n-octylaluminium, methylaluminium dichloride,ethylaluminium dichloride, dimethylaluminium chloride, diethylaluminiumchloride, aluminium isopropoxide, ethylaluminiumsesquichloride,methylaluminiumsesquichloride, methylaluminoxane (MAO), ethylaluminoxane(EAO), and modified methylaluminoxane (MMAO).

A fifteenth aspect of the present disclosure may include any of thefirst through fourteenth aspects, where the co-catalyst comprises areaction product of the antifouling compound and methylaluminoxane.

A sixteenth aspect of the present disclosure may include any of thefirst through fourteenth aspects, where the co-catalyst comprises areaction product of the antifouling compound, methylaluminoxane, and analkyl aluminum compound.

A seventeenth aspect of the present disclosure may include any of thefirst through sixteenth aspects, where the molar ratio of theantifouling compound to the organoaluminum complex is from 0.001 to 1.

According to an eighteenth aspect of the present disclosure, a methodfor tetramerizing ethylene to form 1-octene may comprise contactingethylene with a catalyst system of any of the first through sixteenthaspects to form a product comprising 1-octene.

A nineteenth aspect of the present disclosure may include the eighteenthaspect, where ethylene is formed in conditions of a reactor pressurefrom 5 bar to 120 bar; and a reactor temperature from 25° C. to 180° C.

The subject matter of the present disclosure has been described indetail and by reference to specific embodiments. It should be understoodthat any detailed description of a component or feature of an embodimentdoes not necessarily imply that the component or feature is essential tothe particular embodiment or to any other embodiment. Further, it shouldbe apparent to those skilled in the art that various modifications andvariations can be made to the described embodiments without departingfrom the spirit and scope of the claimed subject matter.

For the purposes of describing and defining the present disclosure it isnoted that the terms “about” or “approximately” are utilized in thisdisclosure to represent the inherent degree of uncertainty that may beattributed to any quantitative comparison, value, measurement, or otherrepresentation. The terms “about” and/or “approximately” are alsoutilized in this disclosure to represent the degree by which aquantitative representation may vary from a stated reference withoutresulting in a change in the basic function of the subject matter atissue.

It is noted that one or more of the following claims utilize the term“wherein” as a transitional phrase. For the purposes of defining thepresent technology, it is noted that this term is introduced in theclaims as an open-ended transitional phrase that is used to introduce arecitation of a series of characteristics of the structure and should beinterpreted in like manner as the more commonly used open-ended preambleterm “comprising.”

It should be understood that where a first component is described as“comprising” a second component, it is contemplated that, in someembodiments, the first component “consists” or “consists essentially of”that second component. It should further be understood that where afirst component is described as “comprising” a second component, it iscontemplated that, in some embodiments, the first component comprises atleast 10%, at least 20%, at least 30%, at least 40%, at least 50%, atleast 60%, at least 70%, at least 80%, at least 90%, at least 95%, oreven at least 99% that second component (where % can be weight % ormolar %).

Additionally, the term “consisting essentially of” is used in thisdisclosure to refer to quantitative values that do not materially affectthe basic and novel characteristic(s) of the disclosure. For example, achemical composition “consisting essentially” of a particular chemicalconstituent or group of chemical constituents should be understood tomean that the composition includes at least about 99.5% of a thatparticular chemical constituent or group of chemical constituents.

It should be understood that any two quantitative values assigned to aproperty may constitute a range of that property, and all combinationsof ranges formed from all stated quantitative values of a given propertyare contemplated in this disclosure. It should be appreciated thatcompositional ranges of a chemical constituent in a composition shouldbe appreciated as containing, in some embodiments, a mixture of isomersof that constituent. In additional embodiments, the chemical compoundsmay be present in alternative forms such as derivatives, salts,hydroxides, etc.

What is claimed is:
 1. A catalyst system suitable for tetramerizingethylene to form 1-octene, the catalyst system comprising: a catalystcomprising a reaction product of a chromium compound and a ligand havingthe structure:(R₁)(R₂)A-B-C(R₃)(R₄) wherein: A and C are independently chosen fromphosphorus, arsenic, antimony, bismuth, and nitrogen; B is a linkinggroup between A and C; R₁, R₂, R₃, and R₄ are independently chosen froma (C₁-C₅₀) hydrocarbyl or a (C₁-C₅₀) heterohydrocarbyl; and aco-catalyst comprising a reaction product of an organoaluminum compoundand an antifouling compound, wherein the antifouling compound comprises:one or more quaternary salts; one or more organic acids, organic acidsalts, esters, anhydrides, or combinations of these; one or morechlorinated hydrocarbons, chloro-aluminum alkyls, or combinations ofthese; one or more polyether alcohols; or one or more non-polymericethers.
 2. The catalyst system of claim 1, wherein the antifoulingcompound comprises one or more quaternary salts.
 3. The catalyst systemof claim 1, wherein the antifouling compound comprises one or moreorganic acids.
 4. The catalyst system of claim 1, wherein theantifouling compound comprises one or more organic acid salts.
 5. Thecatalyst system of claim 1, wherein the antifouling compound comprisesone or more esters.
 6. The catalyst system of claim 1, wherein theantifouling compound comprises one or more anhydrides.
 7. The catalystsystem of claim 1, wherein the antifouling compound comprises one ormore chlorinated hydrocarbons.
 8. The catalyst system of claim 1,wherein the antifouling compound comprises one or more chloro-aluminumalkyls.
 9. The catalyst system of claim 1, wherein the antifoulingcompound comprises one or more polyether alcohols.
 10. The catalystsystem of claim 1, wherein the antifouling compound comprises one ormore non-polymeric ethers.
 11. The catalyst system of claim 1, whereinthe chromium compound comprises one or more of an organic chromium salt,an inorganic chromium salt, and a chromium complex.
 12. The catalystsystem of claim 1, wherein the chromium compound comprises one or moreof chromium trichloride tris-tetrahydrofuran complex,(benzene)tricarbonyl chromium, chromium (III) octanoate, chromium (III)acetylacetonoate, chromium hexacarbonyl, and chromium (III)2-ethylhexanoate.
 13. The catalyst system of claim 1, wherein theorganoaluminum compound has the structure:

wherein R₆, R₇, and R₈ are each selected from a hydrogen atom and a(C₁-C₂₀) hydrocarbyl group.
 14. The catalyst system of claim 1, whereinthe organoaluminum compound comprises one or more of trimethylaluminium,triethylaluminum, tripropylaluminum, tri-iso-butylaluminum,diisobutylaluminium hydride, trihexylaluminum, tri-n-octylaluminium,methylaluminium dichloride, ethylaluminium dichloride, dimethylaluminiumchloride, diethylaluminium chloride, aluminium isopropoxide,ethylaluminiumsesquichloride, methylaluminiumsesquichloride,methylaluminoxane (MAO), ethylaluminoxane (EAO), and modifiedmethylaluminoxane (MMAO).
 15. The catalyst system of claim 1, whereinthe co-catalyst comprises a reaction product of the antifouling compoundand methylaluminoxane.
 16. The catalyst system of claim 1, wherein theco-catalyst comprises a reaction product of the antifouling compound,methylaluminoxane, and an alkyl aluminum compound.
 17. The catalystsystem of claim 1, wherein the molar ratio of the antifouling compoundto the organoaluminum complex is from 0.001 to
 1. 18. A method fortetramerizing ethylene to form 1-octene, the method comprisingcontacting ethylene with a catalyst system of any of claim 1 to form aproduct comprising 1-octene.
 19. The method of claim 18, wherein theethylene is formed in the conditions of: a reactor pressure from 5 barto 120 bar; and a reactor temperature from 25° C. to 180° C.